A mass cytometry approach to track the evolution of T cell responses during infection and immunotherapy by paired T cell receptor repertoire and T cell differentiation state analysis

T cell receptor (TCR) recognition followed by clonal expansion is a fundamental feature of adaptive immune responses. Here, we developed a mass cytometric (CyTOF) approach combining antibodies specific for different TCR Vα- and Vβ-chains with antibodies against T cell activation and differentiation proteins to identify antigen-specific expansions of T cell subsets and assess aspects of cellular function. This strategy allowed for the identification of expansions of specific Vβ and Vα chain expressing CD8+ and CD4+ T cells with varying differentiation states in response to Listeria monocytogenes, tumors, and respiratory influenza infection. Expanded Vβ chain expressing T cells could be directly linked to the recognition of specific antigens from Listeria, tumor cells, or influenza. In the setting of influenza infection, we showed that the common therapeutic approaches of intramuscular vaccination or convalescent serum transfer altered the clonal diversity and differentiation state of responding T cells. Thus, we present a new method to monitor broad changes in TCR specificity paired with T cell differentiation during adaptive immune responses.

Gut germinal center regeneration and enhanced antiviral immunity by mesenchymal stem/stromal cells in SIV infection

Although antiretroviral therapy suppresses HIV replication, it does not eliminate viral reservoirs or restore damaged lymphoid tissue, posing obstacles to HIV eradication. Using the SIV model of AIDS, we investigated the effect of mesenchymal stem/stromal cell (MSC) infusions on gut mucosal recovery, antiviral immunity, and viral suppression and determined associated molecular/metabolic signatures. MSC administration to SIV-infected macaques resulted in viral reduction and heightened virus-specific responses. Marked clearance of SIV-positive cells from gut mucosal effector sites was correlated with robust regeneration of germinal centers, restoration of follicular B cells and T follicular helper (Tfh) cells, and enhanced antigen presentation by viral trapping within the follicular DC network. Gut transcriptomic analyses showed increased antiviral response mediated by pathways of type I/II IFN signaling, viral restriction factors, innate immunity, and B cell proliferation and provided the molecular signature underlying enhanced host immunity. Metabolic analysis revealed strong correlations between B and Tfh cell activation, anti-SIV antibodies, and IL-7 expression with enriched retinol metabolism, which facilitates gut homing of antigen-activated lymphocytes. We identified potentially new MSC functions in modulating antiviral immunity for enhanced viral clearance predominantly through type I/II IFN signaling and B cell signature, providing a road map for multipronged HIV eradication strategies.

The current state of immunotherapy for primary and secondary brain tumors: similarities and differences

Treatment and resolution of primary and metastatic brain tumors have long presented a challenge to oncologists. In response to the dismal survival outcomes associated with conventional therapies, various immunotherapy modalities, such as checkpoint inhibitors, vaccine, cellular immunotherapy and viral immunotherapy have been actively explored over the past couple of decades. Although improved patient survival has been more frequently noted in treatment of brain metastases, little progress has been made in improving patient survival in cases of primary brain tumors, specifically glioblastoma, which is the representative primary brain tumor discussed in this review. Herein, we will first overview the findings of recent clinical studies for treatment of primary and metastatic brain tumors with immunotherapeutic interventions. The clinical efficacy of these immunotherapies will be discussed in the context of their ability or inability to overcome inherent characteristics of the tumor as well as restricted antigen presentation and its immunosuppressive microenvironment. Additionally, this review aims to briefly inform clinicians in the field of neuro-oncology on the relevant aspects of the immune system as it pertains to the central nervous system, with special focus on the differing modes of antigen presentation and tumor microenvironment of primary and metastatic brain tumors and the role these differences may play in the efficacy of immunotherapy in eradicating the tumor.

[Attitudes of students of medicine, sociology and jurisprudence towards autopsy]

Attitudes of students of medicine, sociology and jurisprudence towards autopsy.

SUBJECT

The autopsy is an important instrument of quality control in medicine. Nevertheless, we observe a dramatic decrease of post-mortem examinations. Because physicians take a important role as mediators, we tried to examine the attitudes of medical students towards autopsy and possible differences to students of other faculties.

PROBANDS AND METHODS

Data of medical students (n = 335), students of jurisprudence (n = 95), and of sociology (n = 26) at Leipzig University were collected with the help of a specially elaborated questionnaire >>Post-mortem Examination<< (Fragebogen zur Sektion, FBZS), and two questionnaires >>Death and Dying<< (Fragebogen zu Tod und Sterben, FIMEST) and >>Personality<< (Persönlichkeitsfragebogen, Giessen-Test).

RESULTS

Referring to the attitudes towards post-mortem examination there is only a slight difference between students of the above-mentioned faculties. Even preclinical students showed no difference with their attitudes towards autopsy compared to the students of other faculties and they showed lack of knowledge and ethical doubts towards autopsy.

CONCLUSION

Due to the significant lack of knowledge of the medical students of the University of Leipzig it seems questionable, if they will be able to convince relatives to give consent to an autopsy in later activity as physicians. More instructional work during study and further medical education should be done.